How to Evaluate WasteNot During a Trial

A WasteNot trial answers one question: can you reduce wasted paid-media spend by keeping the wrong audiences out of the wrong campaigns?

The best trial is simple. Connect your core customer data, apply one or two high-confidence exclusion audiences to the campaigns where waste is most likely, and compare results against a recent baseline. You don't need to rebuild your media strategy to find out whether WasteNot is helping.

A successful trial does not have to prove that every campaign changed overnight. It should show whether WasteNot can shift spend away from customers who were already likely to buy and toward the prospects your acquisition campaigns were meant to reach. Results depend on your data quality, ad platform setup, campaign structure, audience size, and how much of your current budget is being spent on the wrong audiences — which you may not know going in, and which is often one of the most useful findings of a pilot.

What to test first

Start with the campaigns where wasted spend is easiest to identify:

• Prospecting campaigns that should focus on new customers

• Campaigns struggling with high nCAC, low new-customer purchase percentage, or a high share of spend reaching the wrong audiences

• Broad Meta or Google campaigns that may drift toward warm traffic or existing customers

• Campaigns with high spend and unclear new-customer contribution

• Campaigns where past customers, subscribers, or recent purchasers should not be the primary audience

For most teams, the first trial should not try to solve every segmentation problem at once. Start with a clear exclusion rule, such as past customers or recent purchasers, and apply it to a small set of campaigns where the expected impact is easiest to measure.

Connect your main data source

Connect the source that gives WasteNot the clearest view of your customers. For ecommerce brands, this is usually Shopify. Other useful sources include Klaviyo, Stripe, Recharge, Attentive, a data warehouse, or another system that stores customer, order, subscription, or engagement data.

WasteNot uses these sources to understand who belongs in each audience. The better the source data, the more useful your exclusion rules will be.

A good first setup usually includes:

1. Your commerce or order source

2. Your main email/SMS engagement source, if available

3. The ad platform where you want to apply exclusions

See Data Sources for connector setup guidance.

Choose your primary success metric

Pick the metric that best reflects what you are trying to improve. Common trial metrics include:

Metric	What it helps answer
nCAC	Are we acquiring new customers more efficiently?
New customer purchases	Are more first-time customers coming through?
Share of purchases from new customers	Is paid media shifting toward true acquisition?
Wasted spend eliminated	Are fewer dollars going to existing customers or warm audiences?
MER or blended efficiency	Is overall spend efficiency improving without overfocusing on platform-reported ROAS?

Most teams should use nCAC (cost per new customer purchase) as the primary trial metric. Platform-reported ROAS can be useful context, but it can also look stronger when campaigns are over-serving existing customers. For this reason, we suggest looking at both in-platform metrics like nCAC and blended metrics like AMER (Acquisition Marketing Efficiency Ratio — all new customer purchases from all channels divided by ad spend in the channel where exclusions are applied).

See Understanding nCAC and Performance Reports for related concepts.

Establish a baseline

Before applying WasteNot, capture a short baseline period. A common starting point is the previous 7, 14, or 30 days.

Use a period that is representative of normal performance. Avoid comparing against a period with major promotions, unusual inventory changes, a site outage, a campaign restructure, or other factors that would distort the trial.

For the baseline, record:

• Total ad spend

• New customer purchases

• nCAC

• Returning customer purchase share from acquisition campaigns

• Campaigns included in the test

• Audience sync status, if applicable

• Any major promotions or campaign changes during the period

Apply a small number of exclusion audiences

Start with a rule that is easy to understand and defend.

Common first-trial audiences include:

• Past purchasers

• Recent purchasers

• Current subscribers

• High-engagement email or SMS contacts

• Frequent recent site visitors

Apply the audience to the campaigns where those users should not be receiving acquisition spend. For example, past purchasers may be excluded from prospecting campaigns but still allowed in win-back, loyalty, or retention campaigns.

Limit other changes during the test

During the trial, avoid changing too many things at once. If you launch new campaigns, change budgets dramatically, add new offers, or update conversion goals during the trial, it becomes harder to understand what changed because of WasteNot.

That does not mean your account must stay frozen. It means the trial should have a written log of what changed and when.

A clean test log should include:

• Date WasteNot was connected

• Date each audience was activated

• Campaigns or ad sets where the audience was applied

• Any budget changes

• Any promo, creative, landing page, or offer changes

• Any tracking or attribution changes

Review performance after the test window

After the first test window, compare your results to the baseline. WasteNot can provide templated reports pulled from your ad platforms, but we recommend also tracking performance internally as you would for any other ad optimization.

Look for directional improvements such as:

• Lower nCAC

• Higher new customer share

• More first-time purchasers at similar or lower spend

• Fewer returning customers attributed to acquisition campaigns

• Improved blended efficiency

Do not judge the trial by a single ad platform's reported ROAS alone. WasteNot is intended to change who your spend reaches. That can improve true acquisition efficiency even when platform-level attribution tells only part of the story.

Trial checklist

Before starting

• Connect your primary customer data source

• Connect your ad platforms

• Pick the campaigns included in the trial

• Choose one primary success metric

• Capture a baseline period

• Decide which audience rule to test first

During the trial

• Confirm audiences are syncing

• Confirm audiences are applied to the intended campaigns, ad sets, or ad groups

• Avoid unnecessary campaign structure changes

• Track any budget, promotion, or creative changes

After the trial

• Compare against the baseline

• Review nCAC and new customer purchase trends

• Check whether acquisition campaigns are reaching fewer existing customers

• Decide which additional audiences or campaigns to test next

What to do next

After the first trial, most teams expand in one of three ways:

1. Apply the same exclusions to more campaigns

2. Add more precise rules, such as exclusions for recent purchasers or current subscribers in specific parts of the funnel

3. Build separate strategies for prospecting, retargeting, win-back, and retention campaigns

Start simple. Prove the first use case. Then expand once you know which audiences and campaigns produce the clearest lift.

Related guides

• Understanding nCAC

• Performance Reports

• Campaign Optimization

• Data Sources